The problem is still going on, but I noticed something I hadn't noticed before : if the Main Page says that there are some new posts, if I go to any forum with supposed new posts, they are all mark read. It looks like there is a problem of communication between each forum and the Main Page...

I noticed something else : I have no "Mark all read" button in the campground forum (maybe it's lacking in a few other forums as well, i didn't check them all). Is there a reason for that?